3d graphics

Jordan Crouse jordan.crouse at amd.com
Wed May 30 11:10:40 EDT 2007

On 30/05/07 13:33 +0200, NoiseEHC wrote:
> Hi!
> I have read through the GeodeLX documentation and I noticed that its DC 
> can output a video stream over the normal (1200x900) frame buffer.
> Can the X11 developers create a mode with the following spec?
> 1. Software can request allocating two YUV (4:2:0 or 4:2:2) frame 
> buffers in the Software's address space with the given dimensions (eg 
> 400x300).
> 2. Software can request displaying one of those frames in the defined 
> size (as I understand the DC will upscale the video if needed).
> 3. Software can render in YUV to one of the frames.
> 4. Software can request flipping to the other frame. (If I read 
> correctly the switch will happen on vsync.)
> 5. goto 3. (The Software can start rendering (vertex 
> transformations/triangle setup/lightning) but have to wait for the vsync 
> somehow...)
> 6. And now we have an usable display system for an OpenGL implementation.

Unfortunately, its not getting the image on the screen thats the problem,
its the rendering and math.  A processor like this just can't keep up
with any serious sort of realtime 3D rendering.  Even with a video overlay
implementation, you still have to render the whole image before sending
it up through Xv, and thats where you will fall down.

But, if you want to try, then be my guest.  The Xv driver has everything
you need to render YUV images to the screen - just make yourself an 
Xv application and swing for the fences.


Jordan Crouse
Senior Linux Engineer
Advanced Micro Devices, Inc.

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